But not by much.
but are they actually any better than phenolic? I know

it can be difficult to re-use a Teflon connector because the heat
necessary to unsolder them can cause the center pin to shift.

If that happens you are using wayyy too much heat.

Teflon will cold flow under tension or pressure, but again that
shouldn't be a problem in a PL-259

IF the center pin shifts with normal soldering then the insulator is not
Teflon, but more likely something like PVC. Many generic connectors of
all types are coming with this cheap thermoplastic as insulators, but
you usually see that in multi conductor connectors such as the DIN
connectors.